A river has a steady speed of vs. A student swims upstream a distance d and back to the starting point.
(a) If the student can swim at a speed of v in still water, how much time tup does it take the student to swim upstream a distance d? Express the answer in terms of d, v, and vs. tup =
(b) Using the same variables, how much time tdown does it takes to swim back downstream to the starting point? tdown =
